Many situations in real life mimic those taught in the classroom. Students who find themselves in a situation where they are employing skill checks that relate directly to a class they have previously taken or are currently taking may make that roll with advantage. Whether or not the skill check relates to the course is up to the DM's discretion and depends on the context of the check. Players are responsible for remembering which courses they have taken/are enrolled in if they want to take advantage (ha) of this mechanic.